Biology – Chapters 15 and 16
Natural Selection and Evolution: Learning Objectives
You may bring this document to the Chapters 15 & 16 test, with notes on one or both sides.
Name Date
By the end of the chapter, students should be able to:
 Explain the difference between a scientific hypothesis and a scientific theory
 Provide examples of at least three scientific theories important to biology
 Explain that Darwin’s theory of evolution (evolutionary theory) explains how organisms evolve because:
 (1) All populations having variation due to mutations/genetic recombination,
 (2) Overproduction in a species produces more offspring than can survive; those that do not
survive often do not reproduce
 (3) Limited resources in ecosystems results in competition for those resources
 (4) Competition leads to natural selection by the environment for those offspring better able to
survive and produce offspring (survival of the fittest and natural selection), and
 (5) The variation in a population (especially the traits that make organisms better able to survive
and reproduce) is passed down to, or inherited by, future generations through DNA.
 Predict the effect on a species if one of the above 5 factors should change. In other words, would evolution
occur if 1) there was no genetic variation in populations or 2) there was no overproduction in a species (i.e.
every organism survived until old age) or 3) resources were widely available so there was no competition or
4) natural selection did not favor any offspring or 5) variation/traits were not inherited?
 Explain the process of speciation, including how populations become isolated form each other
 Behavior isolation, geographic isolation, temporal isolation
 Explain that random changes in the genetic makeup of cells and organisms (mutations) can cause changes
in their physical characteristics or behaviors. If the genetic mutations occur in eggs or sperm cells, the
changes will be inherited by offspring. While many of these changes will be harmful, a small minority may
allow the offspring to better survive and reproduce.
 Explain how mutations are the main sources of heritable variation in a population
 Explain what happens to alleles in a population if the 1) allele results in a trait that reduces the
fitness in an organism or 2) allele results in a trait that increases the fitness in an organism
 Explain what is meant by the “relative frequency” of alleles
 Explain Jean-Baptiste Lamarck’s hypothesis for how living things changed over time, and explain why this
hypothesis is incorrect.
 Explain how some bacteria (like Staphyloccocus aureus) have evolved to become resistant to antibiotics in
the last few years/decades
 Explain that the great diversity of organisms is the result of more than 3.5 billion years of evolution that has
filled available ecosystem niches on Earth with life forms.
 Explain that species alive today are descended with modification from ancestral species. Diverse species
evolving from ancestral species unites organisms into a single “tree of life”. Explain how the millions of
different species alive today are related by descent from a common ancestor.
 Explain that genes in organisms that are very different (e.g., yeast, flies, and mammals) can be very similar
because these organisms all share a common ancestor.
 Explain the types of evidence available that support evolutionary theory, including the following:
 Fossil record (including relative dating and radioactive dating),
 Geographic distribution,
 Homologous features (structures, DNA/genes, embryos)
 The origin of the first prokaryotic cells.
 The origin of the first eukaryotic cells.
 Explain why “intelligent design” is NOT a scientific way to explain the diversity of life found on Earth